Replace a Mechanical Fuel Injection System on 1981 VW Rabbit Diesel - Bosch VE




Introduction: Replace a Mechanical Fuel Injection System on 1981 VW Rabbit Diesel - Bosch VE

About: Married to Domestic_Engineer (but I call her Meghan).

This dives right into replacing a mechanical fuel injection system on a 1981 VW diesel Rabbit with a 1.6L engine.   Bosch VE pump.

Installing pump, injectors, and fuel lines.
Setting timing.

You should still use a service manual, this one is very good but hard to find: 
Volkswagen Rabbit/Scirocco/Jetta Service Manual, 1980-1984: Including Pickup Truck, Convertible, and GTI (Robert Bentley Complete Service Manuals)

This one is less good, but you can get it easy from amazon:
VW Rabbit Diesel 1977 thru 1984 (Haynes Manuals)

Everything is in chronological order -- it starts with the fuel system already out.

A word about the motivation for this instruct able:


"assembly is the reverse of removal"

There are very good reference books for working on cars; Haynes, Chilton,
Bently. However they have a few drawbacks; the first is that
most of the photos are black and white and grainy.  It is not their
fault, it is hard to take pictures inside the engine compartment or
under the transaxle.  The second major drawback is the statement
"assembly is the reverse of removal".  Most manuals are based an a
complete teardown of the vehicle.  This is very useful if you want to
take a car apart peice by peice.  However, once you take the car apart
and have peices all over the garage, spilling out into the drive way
and family room.  You are generaly left with these instructions
"assembly is the reverse of removal."  Even if you follow the
instructions backwards, line-by-line it is very difficult to get
everything back together.  In my opinon these books should start with
a pile of parts and end with a completed vehicle.

So I have started this instructable with parts all over the place and
every bit of timing out of sync.  Hopefully, when you hit the words
"assembly is the reverse of removal", you will find this instructable
and it will help yout out.

Why repair a car from 1981?

55 miles per gallon, no modern emissions rules, cheap parts, and cheap

Why diesel?  Well, check out the work being done by Rudy Behrens of
BEAR Oceanics.

He is building living robotic systems that grow oil rich algea and
process it directly into usable diesel fuel.

Here is a nice article on the project: here

What else do you need to know?

Where to get parts:   -- These are VW specialist, every part has been perfect.  Very good if you want to buy 'kits', such as all new hoses or a complete engine rebuild kit.  They also carry many specialty tools and such.  They are a 'real' store, so you can get them on the phone an they will be able to help, keep in mind that they are also minding the shop, so they might be busy with physical people.  -- Often have the best prices (not always though) good for pretty much anything for any car, but the descriptions are very brief so you need to be careful when ordering.  Fast shipping.

AutoZone is okay, but prices are sometimes high and some parts ship slow, if one part is back-ordered or custom they delay the whole order.  Of course there is probably one near by, so you can go there in person, cheap fluids - expensive tools. I like smaller stores better. 

Local salvage yard  -- In New England you will be about salvage cars tend to be around 10 years old.

Ebay -- I have not had good luck.

Amazon -- Look for deeply discounted professional tools.  I used this and it worked: 
VW/Audi Bosch Diesel Fuel Injection Pump Timing Indicator Tool
Harbor Freight -- most of my car tools are from here, go to the store if you can.  I like the color coded wrenches/sockets.

Home Depot  -- not too useful.

Craigslist -- Look for someone who is getting rid of a garage full of VW parts, or a parts car.

Also  -- The car I am working on is the former ' Clean Machine ' from Gordon Collage in Mass.

Also - I like this wrench set from Harbor Freight because I can remember the colors....  link

Step 1: Why Buy a Rebuilt Pump?

You will need a working pump, I recommend buying a rebuilt pump.  Rebuilding these pumps is hard.  Even if you get it back together, there are several important calibrations that can't be done at home.  The injection pump controls everything the engine and prevents run-away acceleration.

Here are some pictures of a pump rebuild -- I never got this one working correctly.

Step 2: Diesel Fuel Injectors

Diesel engines have fuel injectors instead of spark plugs.  It is a precision part so buy new ones if you can - but they run $50 to $150 each.

Step 3: Heat Sheild

Also get new heat shields.  They say to replace these every time the injectors are removed.

Step 4: Buy a Rebuilt Fuel Injection Pump

The fuel injection pump is complicated and has to be carefully calibrated.

Re-manfuctured they are about $500  -- got mine from Parts Place VW

Step 5: Here Are Some Other Parts That Go on the Pump

These parts are important, but do not come with the pump.  I pulled them off the old one.

Step 6: Install Fuel Injectors

Install the fuel injectors.  Make sure the old heat shields are out.  Put in the new heat shields.  Put a little high temp anti seize lube on the threads.  The injectors have to be tightened correctly; so you need a torque wrench.  The socket is 27mm.

Here is a link to the anti-seize lube on amazon:
Permatex 81343 Anti-Seize Lubricant, 1 oz. Tube

Step 7: Pump Brackets

The pump mounts with 4 bolts.

3 on the face and one at the other end.

One bolt is on a bracket and has to be tightened through a hole in the sprocket.

Step 8: Put This Hose in Place

Now is a good time to put this hose in place.

Step 9: Start Setting the Timing -- Lock the Pump Sprocket

Line up the timing marks on the sprocket and pump.  Then lock the position using this special pin.  It goes through a whole in the sprocket and into a hole on the bracket.

Here is a link to this kit on amazon - 

VW/Audi Bosch Diesel Fuel Injection Pump Timing Indicator Tool

Step 10: Paint the Cover for the Cylinder Head

Paint the cylinder head cover with engine paint.   Clean and sand it first. 

Step 11: Get Flywheel in Right Position (engine to Top Dead Center)

Top dead center -- or TDC -- is sort of the starting point for the engine.  When setting the timing everything gets lined up at TDC.

Line up the timing notch on the flywheel.

Step 12: Set Cylinder Head to TDC

With the cover off the cylinder head - rotate the camshaft to TDC.  Both lobes over the first valve are pointed up and a flat timing tool fits in a slot at the other end.

Step 13: Here Are Timing Marks When It Is a Little Bit Wrong

Setting the timing may take a few tries,  this is what it looks like when you are close, but are not given a cigar.

The pump is lined up but the flywheel is off by about 1cm.

Step 14: Set TDC Again and Install Belt

It is hard to keep everything lined up. 

I had to loosen the sprocket on the camshaft.  To do that, you have to lock the camshaft in place (withouth scratching it), loosen the bolt, then 'tap' the sprocket with a mallet to get it loose.

Now, Set the timing again, jam on the timing belt, then tighten the sprocket again.

Also -- I put graphite on the pump sprocket, this made it much easier to get the belt on.

Step 15: Install the Cold Start Cable

Set the knob so it is pulled out just a little.  Push the cold start lever all the way to the passenger side.  Attach the cable.

Step 16: Cold Start Cable Knob Pulled Out

When starting the engine you pull out this knob.

Step 17: Replace Accellerator Cable

The accelerator cable should be totally replaced, for now I put the old one back on.

The cable hooks on a bracket that is transferred from the old pump.

Step 18: New Fuel Line

Install a fuel line from the filter to the pump, use a clear one.

Step 19: New Gasket for Cover

Install a new gasket for the cover. It has 3 parts.

Step 20: Put the Cover Back On

Put the cove back on.  I sprayed the edges that will touch the gasket with graphite, there was some bare metal and I didn't want to paint it. 

Step 21: Fine Tune the Timing

The timing has to be fine tuned using a dial gauge.  If you have experience you might be able to do this 'by ear' with the motor running.      The gauge is from a kit.

Here is a video that shows the way the pump can be rotated.  It is pretty loose here.

Step 22: Remove This Thing That Is in the Way...

Had to remove this thing to fit the dial gauge in place.  It goes into the side of the pump.

Step 23: Take a Bolt Out of the Pump

There is a bolt in the side of the timing pump.  It is in the center on the drivers side.  This is where the gauge will go.  Take out the bolt, do not loose the washer.

Step 24: Dial in Place

Screw the dial gauge into the hole where the bolt came out of.


when you do the fine tuning with the dial gauge, the cold start knob has to be pushed in

Step 26: Find the Low Point

With the dial gauge in place rotate the engine backwards a little bit.  You are looking for a point where the needle stops moving.
Then set the dial gauge to zero.  Then rotate the engine the normal way to TDC.  Then you rotate the entire pump until the dial gauge shows the correct value, check a book, it is about 1mm.

This sets the amount of fuel that is injected. 

Here is a poor quality video - 

Step 27: At TDC - Calibrate

Set to TDC and read the dial gauge.  This is the value we are trying to get correct.  Look up the calibration value in a book.

Then - loosen the bolts on the injection pump bracket and rotate the entire pump such that the dial is at the calibration value.

Step 28: Tighten the Bolts

With everything perfect, tighten up the bolts holding the pump in place.  The pictures here show me setting the wrong torque and breaking a bolt.  So.... you should do it right and not break anything.

Video of trying to tighten to the wrong torque.  Set to 25 ft/lb instead of 25Nm.

Step 29: Put the Back the Bolt and the Other Pump

If that worked out, remove the dial gauge and replace the bolt with the washer.  Also, put back the thing we had to take off. 

Step 30: Install High Pressure Fuel Lines

The fuel lines that go from the pump to the injectors are metal and curvy.  I bought new ones, but they can probably be cleaned. 

Step 31: Install the Metal Fuel Lines --- Be Gentle

Each fuel line is different.  Fit everything in place loosely.  Don't break anything.  Don't cross thread anything.  Use a light touch.  Get everything 'finger tip' tight.  

Step 32: Tighten Up -- Genlty

Now tighten all the joints.  Tighten just enough -- you don't want to break these.  It will be easy to tighten them latter if there is a leak.  

Step 33: Put Little Fuel Lines Between the Injectors

There are barbed ports on the injectors.  This is for fuel return as not all the fuel gets injected.   Replace these with new hoses. 

The injector all the way to the drivers side is a dead-end.  So you need a plug or to clamp a piece of hose.

Step 34: Wire to Fuel Solenoid

There is a solenoid on the pump that controls the flow of fuel.   

If you have to fix the wire, here is how.

Step 35: Fuel Return Line

Not all the fuel gets injected so it has to go back to the tank.  There is also a low pressure resevoir in the pump which always has fuel going in and out.  There is a tiny hole that must be clear.

Step 36: Power

Everything is now installed... probably.

To test things out we will need some power.  It is hard to start the first time.  I hooked up a giant power supply used to fast charge batteries.

It is good to have a fire extinguisher.  Find a fresh one....

Step 37: Get the Air Out -- Bleed

The pump and all the fuel lines need to be filled up with fuel.

This already has an extra electric pump.  I ran that for a while to get the air out and fuel in.  You can also do this by removing the "out' bolt and pouring fuel in with a funnel -- then slightly unscrew the metal fuel lines at the injector and run the starter motor to get air out. 

Step 38: Crank the Engine -- Does It Work?

To start the engine; pull out the cold start knob. Turn the key part way to turn on the glow plugs.  Put the car in neutral and set the hand brake.

Here is a video of the engine running.

Notice that no exhaust comes out the tail pipe, so there is a big hole somewhere...

Step 39: Video of Engine Not Running

Here are some videos where nothing works and nothing happens.

More of the same.

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    Question 3 years ago on Step 35

    Hi, do you know the size of the larger return hose that comes out of the OUT port on the injection pump?


    7 years ago on Introduction

    How did you get the sprocket on the timing pump back on? I needed a 5 ton puller just to get the darn thing off :(


    7 years ago on Step 11

    I have a 1984 VW Transporter 1.6 Diesel and I can't find a mark on the flywheel so that I can get TDC. What do I do?


    Reply 7 years ago on Step 11

    Sorry for the slow reply --

    The marks on the flywheel are really hard to see. You might try having someone else slowly rotate the engine while you watch the flywheel.

    There are two other ways to do it:

    1 - Remove the fuel injector closest to the timing belt. Stick something in the hole that won't scratch the cylinder (like a chopstick or a plastic welding rod). Rotate the engine. When the stick is at the highest point it is at TCD.

    2 - You can also remove the crankase cover and look at the lobes on the camshaft. Look at the piston #1 (closest to the sprocket). Rotate the engine until both lobes are up. At TDC the first lobe points to the front of the car and the second points towards the back.


    9 years ago on Step 7

    That metal arm that you bolt to the left bracket - what does it do? Does it have nuts on the end of the two bolts?
    I found mine fallen off beneath the pump - hoping that there's some way to attach it without removing the whole injection pump.


    Reply 9 years ago on Introduction

    The photo is misleading -- the metal arm goes on the outside of the injection pump mounting holes, So the injection mounting holes are between the metal arm and the passenger side (left) bracket. As far as I can tell, the only purpose of this weird piece is to hold the bottom mounting bolt in place while you put a nut on it. It is falls off, but the injection pump is still on tight (can't be moved by hand, no matter how hard you try), then it should be fine.

    Here are the details that I can recall:

    The top bolt passes through the top hole in the metal arm, then through the pump mounting holes, then into a threaded hole in the left bracket.

    The bottom bolt is attached to the metal arm, it passes through the pump mounting holes then through a non-threaded hole in the left bracket, and it is fastened with a nut. This nut is hard to get to, you have to line up a hole in the sprocket with the bolt, then pass the nut through the sprocket and tighten to the bolt.

    In step 28, you can see that I screw this up and break the bolt.


    Reply 9 years ago on Introduction

    Thanks - that's super helpful!

    Indeed, I just found the third securing bolt fallen off, and the injection pump is loose, which would explain why the engine is running so rough, even though the drive-belt is tensioned properly.

    Since I don't have a dial gauge, and the drive belt has not been removed, I think I can just line up the line on the pump with the line on the bracket and tighten the bolts down?


    Reply 9 years ago on Introduction

    Yeah -- line everything up, then you can fine tune it by ear. With the engine running and the bolts pretty tight, you can slightly rotate the pump by hand until it seems like it is idling well. Then tighten everything up.

    You can can also start with the pump rotated to far in one direction (so it injects late, I think this is with the pump to far towards the engine), then rotate the pump to advance the timing until is sounds correct (away from the engine, I think).

    I might do the same thing this weekend, you've reminded me that I have to replace that same lower bolt. I thought my engine mounts were bad (which I am sure they are) but maybe the timing is just off.


    Reply 9 years ago on Introduction

    Just my 2¢ on advancing the pump...

    To advance the injection timing, you rotate it (the top of the pump) towards the engine. I just did it (with a dial gauge) about an hour ago. A little movement does quite a bit of adjustment, so don't go to the stops! There will be too much advance if you do (assuming all is at TDC).


    8 years ago

    I was so lost trying to reconnect wiring , until I found your photos .
    Thank you much .


    9 years ago on Introduction

    Thank you, - The info about using the Cold Start on Diesel Rabbit is very useful for me. (for a fiction writing project of all things) .

    I have a Diesel Toyota (Landcruiser with 2h engine) . It uses the older inline 'jerk pump' injection system and pre-combustion chambers, and will run on about anything oily, including kero blends.
    The Glow plugs act as a Hot Spot in 2h engines, to help ignite the beginning of each spray of diesel - quickly. Sprays of diesel must burn as it enters engine so there is never much unburnt fuel. Lag in ignition of the spray will result in KNOCK as the unburnt spray ignites - BANG - which breaks pistons.

    My 12v glow controller cost more than the truck , so I replaced with it with a piece of wire and a verbal countdown (of magical mechanic words), when key is in glow position. It starts and runs fine so long as I remember to use full throttle, - required in old bosch vacuum governed pumps. - and yes it does have a throttle plate for to make a small vaccum for the governor. That vacuum represents a pumping loss when the engine is running.

    thank you for your instrucables on injection system changeout , and the aquaponics .


    10 years ago on Introduction

    Marc, this is a great instructable! Thanks for contributing. I own a modern common rail injection diesel car, but seeing how the old ones work is great. Thanks for this tremendous piece of work!



    Reply 10 years ago on Introduction

    Hi Koray -- Thanks so much for your kind comments -- I figure, if I don't finish the car, at least I'll have posted some instructables! - Marc